Common Name: Black Walnut
Scientific Name: Juglans nigra
Other Names: American Walnut, American Black Walnut, Eastern Black Walnut.
Leaf: Yellowish green, yellow in fall; smooth above, hairy beneath; 20-60 cm long; 14-22
short-stalked leaflets; middle leaflets smaller than leaflets at end; terminal leaflet
missing or much smaller.
Flower: Pollen flowers and seed flowers on the same tree; pollen flowers with 20-30
stamens, catkins 5-10 cm long; erect seed flowers in clusters of 1-4.
Fruit: Yellow-green to brown; spherical, 4-6 cm in diameter; dropping clusters of 1-3;
husk slightly hairy; nut surface has deep grooves, smooth topped ridges; kernal has
strong flavour, oily.
Twig: Stout; orange-brown, slightly hairy, pith is orange-yellow.
Bark: Light-brown when young, dark brown when mature; scaly when young, rounded almost
intersected ridges when mature.
Wood: Heavy, hard, strong; dark brown to black; sapwood nearly white; straight-grained;
resistent to decay.
Facts About This Tree:
1. Black walnut is uncommon in Canada but found naturally in southern Ontario. It is
planted for its fruits and as an ornamental.
2. It is valued for its wood which is easy to work with, does not shrink or warp, and has
an attractive grain. However, they are intolerant of shade. It is the most priced
hardwood in North America.
3. Walnut husks contain poison and so were used to make insecticides and fish poisons.
The roots and decaying leaves release a toxin in order to prevent competition from other
Lat, Long: 43.78394, -79.59163
Diameter (DBH): 20.4 cm
Last Year Modified: 2015
Carbon Stored in this Tree: 72.51 kg of C
Equivalent CO2: 265.85 kg of C
1. Farrar, J. L. 2007. Trees in Canada. ON. Canadian Forest Service.
2. Kershaw, Linda. 2001. Trees of Ontario. Edmonton, AB Canada. Lone Pine Publishing.
3. Photo Credit: Susan Sweeny. 2004. Retrieved on July 8, 2015 from
4. Photo Credit: Susan Sweeny. 2004. Retrieved on July 8, 2015 from
5. Photo Credit: Susan Sweeny. 2004. Retrieved on July 8, 2015 from
6. Photo Credit:(c)2007 Derek Ramsey (Ram-Man). Location credit to the Chanticleer Garden.
(Self-photographed) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0
(http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons.
7. Photo Credit: MONGO. 2006. Retrieved on July 8, 2015 from
8. Photo Credit: I, Jean-Pol GRANDMONT [CC BY-SA 3.0
(http://creativecommons.org/licenses/by-sa/3.0) or CC BY 2.5
(http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons.
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